Raykov, Tenko
Routledge, Taylor & Francis Group, 2008
Buku Teks
Tabachnick, Barbara G.
Allyn and Bacon, 2001
Buku Teks
Gnanadesikan, Ram, 1932-
John Wiley & Sons, 1977
Buku Teks
Cooley, William W.
John Wiley & Sons, 1971
Buku Teks
Dunteman, George Henry
Sage Publications, 1984
Buku Teks